Re: [PATCH net v2 1/2] ipv6: serialize address publication with device teardown

[Ido Schimmel]

On Wed, Oct 07, 2026 at 07:45:48PM +0300, Ido Schimmel wrote:
> Yes, we need to pass the public address to ipv6_add_addr() so that we
> only publish a fully initialized temporary address in the per-idev list
> and the per-netns hashtable. Something like the diff below. It should be
> another patch in this series.

Thinking about it again, the following diff seems cleaner to me. That
way we don't modify the timestamps after publishing the address.

diff --git a/include/net/addrconf.h b/include/net/addrconf.h
index e6764245995f..0cfc99b4d251 100644
--- a/include/net/addrconf.h
+++ b/include/net/addrconf.h
@@ -87,6 +87,8 @@ struct ifa6_config {
 	u32			preferred_lft;
 	u32			valid_lft;
 	u16			scope;
+	struct inet6_ifaddr	*ifpub;
+	unsigned long		tstamp;
 };
 
 enum addr_type_t {
diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index c90ee6dd7446..df3f25fbab64 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -1155,10 +1155,12 @@ ipv6_add_addr(struct inet6_dev *idev, struct ifa6_config *cfg,
 		ifa->flags |= IFA_F_TENTATIVE;
 	ifa->valid_lft = cfg->valid_lft;
 	ifa->prefered_lft = cfg->preferred_lft;
-	ifa->cstamp = ifa->tstamp = jiffies;
+	ifa->cstamp = jiffies;
+	ifa->tstamp = cfg->ifpub ? cfg->tstamp : ifa->cstamp;
 	ifa->tokenized = false;
 
 	ifa->rt = f6i;
+	ifa->ifpub = cfg->ifpub;
 
 	ifa->idev = idev;
 	in6_dev_hold(idev);
@@ -1487,6 +1489,8 @@ static int ipv6_create_tempaddr(struct inet6_ifaddr *ifp, bool block)
 
 	cfg.pfx = &addr;
 	cfg.scope = ipv6_addr_scope(cfg.pfx);
+	cfg.ifpub = ifp;
+	cfg.tstamp = tmp_tstamp;
 
 	ift = ipv6_add_addr(idev, &cfg, block, NULL);
 	if (IS_ERR(ift)) {
@@ -1497,12 +1501,6 @@ static int ipv6_create_tempaddr(struct inet6_ifaddr *ifp, bool block)
 		goto retry;
 	}
 
-	spin_lock_bh(&ift->lock);
-	ift->ifpub = ifp;
-	ift->cstamp = now;
-	ift->tstamp = tmp_tstamp;
-	spin_unlock_bh(&ift->lock);
-
 	addrconf_dad_start(ift);
 	in6_ifa_put(ift);
 	in6_dev_put(idev);